CytoFlex Flow Cytometer Application Notes

CytoFLEX Research Cytometer Event Rate Settings TECHNICAL INFORMATION BULLETIN

Pulse Area: The integration of the area under the curve formed from the pulse width and intensity as the particle moves through the collection point.

Digital flow cytometers use optical sensors to collect light signals and convert them into electronic signals to represent the light events occurring in the flow cell of the instrument. The conversion of the light signal into an electronic signal allows for the digital quantification and measurement of the signal event. The Voltage Pulse The digital information recorded by a flow cytometer indicates the total light signal collected across the event as a particle moves into and across a laser’s path.

Pulse Width

Gating Window

Detection Threshold

Pulse Intensity

LASER

(DT)

Time

Figure 2

LASER

The Pulse Parameters: The Gating Window In most digital f low cy tometers electronic signals are continuously being collected even if no particle is being passed through the collection point. To distinguish background from real signals, an electronic cutoff called the detection threshold is established for each experiment and this determines the signal intensity where the electronic system will begin to record and measure a voltage pulse (Figure 2, orange dotted line, labeled Detection Threshold (DT). The length of time that the machine records the signals above threshold is referred to as the gating window (GW). (Figure 2, and shaded light blue). The electronics within the machine are thus programmed to process any signals that are greater than the DT and occur

LASER

Figure 1

The entire pulse has three characteristics: Pulse Intensity: The strength of the signal as it passes through the data collection point Pulse Width: The period of time that it takes for a particle to pass through a data collection/interrogation point.

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